Class Project: best course of action and resources to quickly learn web services and choose appropriate protocol to interact with Android app

Hi all,

I am currently a CS student, and I'm currently developing an Android application for a mobile development class that will interact with a Drupal-based website. Briefly: the website and application will be based on the StackOverflow model, but for organic/sustainable gardening/farming. Questions/answers will be posted either online or via the Android app, and Android version will need to sync with user account and question/answer data from server. (I can PM more details, if interested.) I hope to eventually implement a badge system and the like.

I have been a happy Drupal user/"developer" for about 1.5 years now (developer in quotes), having developed custom themes, learned Drush, played with views, etc. I'm hoping to up my game in both mobile dev and Drupal dev with this project.

The problem is that I have zero experience with web services, and though I'm making progress slugging through wiki articles/random resources, it's still a difficult trek. The good news is that I have spring break to learn a bunch next week.

I was hoping for direction in:
a) good resources/advice for learning
b) recommendations on which protocol to use based on my specs
c) all other advice. Is this project too much?

SPECS:
- Ability to login. This is a services thing, right?
- Sync user profile data to phone (After having logged in, just parsing XML?)
- Sync Question/Answer data to phone (XML parsing?)

How would I generate the XML files? (I haven't explored the services codebase yet, so my questions are probably really elementary.) Access them? What does this look like at a high level?

I would really appreciate it. Thanks.